Arc quencher



Feb. 23, 1943. F. J. POKORNY 2,311,690

ARC QUENCHER Fil d June 10, 1940 3 Sheets-Sheet l Feb. 23, 1 943.

F. J. PQKORNY ARC QUENCHER Filed June 10, 1940 3 Sheets-Sheet 2 T I i.INVENI'OR.

' ATTORNEY Feb. 23, 1943. F. J; POKORNY ARC QUENCHER 3 Sheets-Sheet 3Filed June 10, 1940 Patented Feb. 23, 1943 UNITED STATES PATENT OFFICEARC QUENCHER Application June 10, 1940, Serial No. 339,683

18 Claims.

This invention relates to circuit interrupting apparatus and arcquenching means, therefore and more particularly to an arc quencher thatis readily mountable and demountable as a unit.

The type of apparatus involved includes power switching equipment thatmay be required automatically to interrupt fault currents of greatmagnitude. These arcing currents, unless extinguished quickly willseriously damage metallic parts with which they come into contact. Suchparts should be periodically inspected and replaced when necessary. Asthese parts are enclosed Within the arc quencher provision must be madefor the easy removal of the extinguishing device and also for securelyclamping it in operative position.

Further the type of power switching apparatus to which this inventionmay be applied, is frequently enclosed in compact metal cubicles as aprotection for the operator and surrounding apparatus. In such aninstallation, vertical space within the compartment is limited so thatit is advantageous to be able to withdraw the arc quencher forwardhorizontally without any vertical movement being required.

Is is, therefore, an object of this invention to provide an arc quencherthat is readily mountable and demountable to and from operative relationwith the separable contacts of a circuit interrupter.

It is a further object of this invention to .provide an arc quencherthat is demountable by a simple horizontal forward movement without anyvertical movement being required.

It is another object of this invention to pro vide an arc quencher thatis a rugged unitary structure and that may be securely held in operativeposition by a single clamping means.

t is an additional object of the present invention to provide aneffective compact arc chute that is composed of inexpensive parts and iseasily manufactured.

There are many other objects and uses of the present invention and ofthe combinations and elements herein set forth. Many of them havealready been pointed out. Many others will in part be apparent and wherenot intrinsically apparent will be pointed out in the followingdescription and drawings, in which:

Figure 1 is a side elevation of the circuit break or of our invention.

Figure 2 is a front view of the circuit breaker arrangement of Figure 1.

Figure 3 is a cross-sectional view on line 3-3 of Figure 2 showing thecircuit breaker in closed circuit position.

Figure 4 is a view corresponding to that of Figure 3 showing the circuitbreaker in open circuit position.

Figure 5 is a cross-sectional view on line 5-5 of Figure 4 showing thearrangement of the arc quencher.

Referring now to Figures 1, 2, 3 and 4, I have here shown a three polecircuit breake comprising the elements of the present invention. Thecircuit breaker consists of a group of pole units 20, 2|, 22 (Figure 2)mounted on the face of an ebony, asbestos or slate panel 23 which formsthe mounting plate of the entire circuit breaker arrangement.

M ain supporting members The main bracket or housing 24 which supportsthe operating members is secured to the panel 23 by means of screws 25,25 the heads of which are recessed in openings 26, 26 in the back of thepanel 23 and which pass through the perforations 21', 21 in said panelto engage the main bracket 24 (Figure 1).

As seen in Figures 1 and 2, the main bracket or housing preferablycomprises two flanged side plates 28 and 29 which extend on each side ofa horizontal shelf 30 to which they are welded. The operating mechanism3| comprising the toggles and other elements hereinafter described isbolted to the lower side of the shelf 30, the housing 300 of the saidoperating mechanism comprising flanges 32, Figures 3 and 4, throughwhich bolts 33 may be passed to engage the shelf 30.

Link 34 connects the operating mechanism 3| to the lever 35 which issecured to the contact shaft and is rotatable therewith. As seen moreparticularly in Figures 3 and 4, the stationary contacts 36 and theirback connection stud assembly are mounted on the panel above the housingor supporting bracket 24 and support the inner end of the arc chutes inthe manner hereinafter described.

A bridge 31 of insulating material secured to the outer end of the mainbracket 24 supports the outer end of the arc chutes in the mannerhereinafter described.

Main and arcing contactsThe stationary main contacts The stationary maincontacts 36 are bolted to the connecting stud 42 by means of the bolts38 and the washers 39. The connecting stud 42 passes through the backpanel 23 and is suitably arranged so that appropriate circuitconnections may be made thereto. The path of the main current when thecontacts are closed, as seen in Figure 3, is through the connection stud42, the stationary contact 36, the stationary contact tip 46, themovable contact tip 4|, the contact lever 69 carrying the flexibleconnection 43 which in turn is electrically connected to the member 44.

Movable contacts support The movable contact shaft 45 is preferably asquare steel bar covered with phenolic insulation molded in place and isrotatably supported in appropriate bearings as hereinafter described.

A contact arm for each pole is mounted on this shaft. The contact arm 46is preferably a bronze casting reinforced by flanges 41 and 48. Thelower end of the bronze casting which engages the square steel shaft ispreferably formed in a V comprising the'members 49 and 50 set atapproximately right angles to each other so that'they will engage thesquare sides of the shaft 45 to which they are to be clamped.

The clamping member comprises also a V- shaped member having the sides52 and 53 which likewise may engage the sides of the square steel shaftand comprising also flanges 54 and 55 through which bolts 56 and 51 maybethreaded to engage the flange 58 and the flat portion 59'of thecontact arm 46 in order to securely clamp the same to the contact shaft45.

As will be noted, especially in connection with Figures 2 and 3, each ofthe main contact arms 46 may be secured to the contact shaft 45 so thatrotation of the contact shaft 45 by the lever 35 will result incorresponding movement of the contact arms 46 for the purpose of openingor closing the circuit.

While any necessary number of contact carrying arms may be mounted uponthe contact shaft as thespecific circuit connections may require onlyone lever 35 is necessary forthe opening and closing operations whichresult in rotation of the shaft 45 and the operation of the variouscontacts.

'In order to obtain a balanced structure it is preferred that the lever35 be secured to the shaft 45 substantially at the center so that themechanism may be properly balanced.

Movable main contacts Each contact arm 46 carries a pair of contactlevers 60 formed and cut from a special copper extruded bar. Each ofthese two levers 66 carries at its upper end a silver nickel contactblock 4| for engaging the stationary main contact tip 49. The back ofthe contact arm 46 has a part-cylindrical depression 6| and the tionbetween the base of the recess 68 and the spring cup 16 which is held inplace on the spring link 66 by the cotter pin 1 I The spring link 66 inextending between the two main contact levers 60 has an eye 66' whichengages a groove 65' in the pin 65 in order to prevent its moving toeither side.

When the main contacts are disengaged in the manner shown in Figure 4,the lower ends 12 of the main contact levers 69 press against thecontact arm 46 in the manner shown.

7 For simplified assembly the only element which retains the pin 63 inplace is the pressure of In the closed position the pressure through thecontact lever 60 between the spring 69 (bearfront of each of the contactlevers has a similar depression 62. A bronze pivot pin 63 is placed inthese depressions. Thi pivot pin has flanges at each side and also aflange in the center between the two contact levers 66 in ordertoprevent any lateral movement of the members with respect to eachother.

Each of the contact levers is drilled at 54 so that a pin 65 may beinserted therein. The pin 65 is preferably of dumbbell shape and acts asan'equalizing yoke between the two contacts 6|l66. A link 66 engages thepin 65 between the two contact levers 6fl60 and is extended up through aperforation 61 in the contact arm 46 into the recessed area 68of saidcontact arm. A compression spring 69 forms the main contact spring andis retained in posiing on the pin 65) and the contact 4| serves tomaintain the adequate pressure necessary to hold the pin 63 in place. Inthe open position, the pressure of the bottom end 12 of the main contactlever 60 against the contact arm 46 and the pull of the compressionspring upon the p n 65 of the lever 60 using the member 12 as a fulcrumserves to maintain the pin 63 in place.

This design of pivot provides long wearing surfaces, The spring link andpressure equalizing pinmay be made of hard steel so that their area ofengagement may be small. The area of engagement at the pin ofthe'contact levers may be of relatively soft material.

The pivot pin engaged by the half-cylindrical surfaces of the contactarm and the contact levers provides a maximum of area for the softerparts. This area could not be obtained in the same width or pin lengthby any other method.

If the levers were formed to rock in a'groove-in the arm, there would becopper and brassbearing surfaces which are far inferior to the steel pinbetween them.

During the closing movement there is no instant when there is anyrelaxation of pressure upon the pin 63, for until the main movingcontact tip 4| is brought into contact with the stationary contact tip40, the bottom end 12 of the contact lever 60 engages the'contact arm 46in the manner shown in Figure 4.

Only after the moving contact tip 4| is in engagement with thestationary contact tip 40 is there a transfer of the fulcrum or the baseof pressure from the portion 12 to the tip 4|. In such case, as has beenseen in connection with the closed position of Figure 3, there is againsufficient pressure to maintain the pin 63 in place.

During the opening movement, pressure is maintained upon the pin 63 byreason of the fact that spring 69 by its pressure on the pin 65 forcescontacts 40 and 4| against each other until, in the rotation of thecontact shaft 45, the end 12 of the contact lever presses againstclamping portion 48 of the contact arm 46, whereupon the base ofpressure is transferred from contact tip 4| to end portion 12. In thismanner, the spring pressure is always exerted to maintain pin 63 inposition.

The rotation of the main contact lever 60 about the pin 62 during theclosing operation necessarily results in a slight sliding motion of themovable contact tip 4| with respect to the stationary contact tip 49 sothat a wiping action occurs tending to clean the contacts.

As seen also in Figures 3 and 4, the back of the contact levers aredrilled and tapped for the securing screws 13 in order to attach theflexible conductor 43 thereto. I

The upper end of the flexible conductor 43 is slit so that separatescrews 13 may attach the separate ends to the two separate contactmembers 60 to allow independent movement of the contacts. Thearrangement of the lever arms above and below the contact pivot is suchthat during heavy current flow the magnetic forces set up will tend toincrease the pressure between the moving and stationary contacts whenthe flow of current is between the stationary contact tip 40 and themovable contact tip 4 I.

By the use of two contact levers of this type for each pole of thecircuit breaker, an adequate contact at each pole is ensured.

Movable arcing contacts The arcing contacts 81 are mounted in the upperpart of the contact arm 45, and are supported by arcing contact levers15. The arcing contact levers 15 preferably are each cut from a bar ofextruded copper and in this case also we have found it preferable to usea pair of such contacts and levers for a single pole. Each of the arcingcontact levers i is pivoted on the pin 76 which is grooved between thecontacts to take a hair pin spring 'I'! which serves to keep the pin 16in center position. A second pin 18 is mounted in the top of the contactarm 45 between two upwardly extending flanges 19 thereof.

An appropriate bushing may be placed between the flanges so that the pinmay be securely riveted over them without bending them. The eye 80 ofthe spring link 8! is placed over the bushing, the said spring link 8!extending beyond the back of the arcing contact levers i5.

Pins 82 having rounded heads are driven into the upper part of the backof the arcing contact lever 15.

A spring cup 83 is pressed against these pins by the compression spring.84 which is held in place on the link 8| by the spring cup 85 at theopposite end which in turn is held in position by the cotter pin 86. Thearcing contact 81 is mounted upon the arcing contact lever and ispreferably formed or cut from an extruded copper bar and is providedwith a contact face 83 preferably of Elkonite silver which is solderedto the copper. Each of the contacts 81 of each of the contact levers '15is held in place upon its contact lever by a socket head cap'screw 89and lock washer 90. As will be seen more particularly in Figure 18, thecontacts 81 are held against turning or other displacements by theshoulder 9| which engages a corner of the arcing contact lever 15. Theends of the contact arm flanges bear against the outer sides of the twoarcing contacts and the projection $2 of the spring link separates thetwo arc ng contacts 8'I-8'I from each other, thus serving adequately toposition them.

As is seen in Figures 3, 4, the lower end of the arcing contact lever'55 is off-set at 93 to receive the end of a flexible conductor 93. Theconductor 93 like the conductor 43 is also slit, the ends thereof beingriveted at the off-set 93' to the arcing contact lever '15 by means ofthe rivet 94 passing through the washer plate 95.

The off-set 93' is curved away at 96 from the I flexible conductor andthe washer plate 95 is curved away at 91 therefrom for the purpose ofpreventing kinking during operation. This flexible conductor 93 is leddown to the lower terminal block 44 to which it is connected by the samescrews 98 that hold the main contact lead 43.

The main contact levers, in contact open position, are held againsttheir fulcrums and against a stop on the arm by a compression spring atthe back of the arm, acting on a link connected to the two contactlevers between the fulcrum and the stop. The contact surface is at thetop of the lever above the fulcrum. The flexible conductor is secured tothe bottom of the lever below the fulcrum.

When the shaft and arm are moved to contact closed position, the contactends of the levers are rotated about their fulcrums and pushed back fromtheir advanced position, moving the bottom stop clear of the arm. Thiscompresses the spring and increases the contact pressure. The use of asingle spring and link between the two levers permits the pin to act asan equalizing yoke.

The attachment of the flexible conductor below the fulcrum causes themagnetic forces to balance about the fulcrum so that the contactpressure may remain the same or increase during fault current.

The auxiliary or moving arcing contacts are mounted at the top of thearm. In this case the spring is above the fulcrum and below thedetachable contact tips. Equalization of pressure is arranged in thesame way. Maintained pressure during fault or inrush current is providedin the same manner.

Ooercurrent coil connections It should also be noted that the flexiblelead I06 from the arcing horn hereinafter described also connected tothe terminal block 44. It will thus be seen that the three flexibleconductors I00, 93 and 43 are all led from the contact structure to thelower terminal 44 to which all three to the current rating of thecircuit breaker, one

terminal of the coil being connected to the lower terminal post 44 andthe opposite end of the coil being connected to the back connection studII which has the securing block I I2 welded to it at the face of thepanel 23.

The back connection stud III is held in place in the panel 23 by thescrews H3 and II 4 which pass through and engage the clip I I5. Theterminal post 44 is bolted in place on the panel 23 by means of thebolts I I6 and lock washers H 7. In other words, therefore, the currentis not led di rectly to the back connection stud I I I but through thelower terminal post 44 and through the coil III] of the over currentmagnet to the back connection stud I I I through which the connection ismade to the circuit.

The coil I I0 of the over current magnet is therefore connected inseries with the contacts.

It might here be noted that the upper back con nection stud 42 islikewise connected through the panel 23 by means of screws I I8 and I I9engaging and passing through the clip I23 and is therefore held inposition in the same manner as the lower back connection stud III.

When the circuit breaker therefore is closed, the current flowing intothe upper stud 42 enters the main contact block 36, passes through themainstationary'contact surface 40 to the main movable contact surface 4|and into the main contact lever 60 passing therefrom through theflexible lead 43 to the lower terminal block .44 around and through thecoil I I to the lower back connection stud III and thence back to thecircuit to which the same is connected.

The over-current coil I I0 will thus be in series with the maincontacts; and, after these are opened, with the arcing contacts; and,finally, with the arcing horns; since the leads 43, 93 and I00 each areconnected to the pigtail post 44.

The arcing contact circuit is in parallel with the circuit through themain contact tips 40 and 4|. The arcing contacts are designed to makebefore and separate after the main contacts during the closing andopening so that as is hereinbeiore described, the arc particularlyduring the opening may be made between the arcing contacts so that themain contacts which carry the load' should not be roughened or distortedto offer any substantial resistance to the passage of current.

Blow out magnet and stationary arcing conta t The current path from thearcing contact tip 08 to the arcing contact lever I and through theflexible lead 93 to the lower terminal block 44 has been described. Themovable arcing contact tip 88 engages the stationary arcing contact tipI2I. Current is led to the stationary arcing contact tip |2I in thefollowing manner:

Current from the upper connection stud 42 flows into the lower terminalI25 of the blow out magnet coil I22 around the coil to its upperterminal I29 and thence to the stationary arcing contact I23. From thestationary arcing contact, the current flows to the stationary arcingcontact tip I2I, thence to the movable arcing contact tip 88, thencethrough the arcing contact lever I5, flexible lead 93, the terminalblock 44, the coil H0, and the connection stud III in the mannerhereinbefore described.

The arcing contacts, particularly the movable arcing tip 81-88, mayreadily be replaced after the same have become worn. When the circuitbreaker is closed, the resistance of the circuit through the maincontacts 39 and 60 is low as compared with the resistance through thearcing circuit so that a relatively small current flows through thelatter.

The main stationary contact 36 is attached to the back connection studas is the lower terminal of the blow-out magnet coil I22 by means ofscrews 38. Screws II9 passing through panel 23 serve to fasten the lowerterminal of blow out magnet coil I22 and angle clip I to panel. Screws 8in turn fasten back connection stud 42 to the angle clip I20. Theelectrical connection between the back connection stud 42 and the lowerterminal I of the blow out magnet coil I22 is made by direct contactbetween the angle clip I20 and the screw I I9 as well as by the directpressure of the terminal I25 against the connection stud 42.

The coil consists preferably of a strip of bar copper wound in a helix,the lower end at I26 being sweated and pinned by pins I21 and I28 to thelower coil terminal I25 and the upper end being secured to a fiat plateterminal I29 which lies against the panel I23. The coil is wound so thatcurrent flowing from the lower coil terminal to the upper coil terminalflows around the slotted cylindrical iron core I30 in a clockwisedirection in the views of Figures 3 and 4.

A fiber tube |3| insulates the core I30 from the coil I22. Insulatedside plates I32 are fastened on each side of the coil terminals. Thearcing terminals I23 also cut from an extruded brass bar is secured tothe upper coil terminal I29 and the panel 23 by screws I33, threadedinto the nut plate I34 which is further anchored in position to providea secure attachment of the members by the screws I35, the heads of whichare embedded in the recess I36 so that they may not interfere with thesecurement of the coil terminal I29 to the panel.

The upper part I38 of the arcing contact I23 is extended along the paneland forms a hook I39 for anchoring the arc chute in the mannerhereinafter described.

The arcing contact I23 curves around the blow out coil as seen inFigures 3 and 4 and forms an arcing horn. The arcing contact ispreferably wider than the coil I22' and as seen in Figures 3 and 4, itsunder surface rests against theedges of the insulating side plates I32.As has been above described, the arcing contact tip I2I is at the lowerend of the arcing contact I23 and is preferably a contact surface ofElkonite silver.

As seen in Figure 2, the contact shaft 45 is a square steel bar which asabove described is covered with phenolic insulation molded in place.Each end of this shaft is drilled at |40a to receive the bearings I40.The shaft itself extends betwen the side plates 28 and 29. The bearingsare brass cylinders inserted in holes in the sides plates to which theirdrilled flanges |4| are secured by screws I42.

When the screws I42 are removed and the two bearings at each end arewithdrawn, the shaft and the entire contact assembly may be removed frombetween the side plates provided of course that the flexible leads havebeen disconnected and also provided that the connection between the link34 and the arm 35 of the contact shaft are separated.

Assembly and operation of the contacts The contact arms 46 are securedto the contact shaft by clamp members 5| which are held in place by apair of screws 56 and 51 on each side of the shaft.

The outside poles are suitably positioned by the contact arm caps orclamps 5Ia while the middle pole arm is held in position by the cap 5|.As is seen more particularly in Figure 3 the clamp or cap 5| is extendedto form the shaft actuating arm 35 and is drilled to receive pin 2I0 inthe upper end of the main toggle link 34. A movement of the operatingmechanism 3| will raise or lower the pin 2|0, therefore raising orlowering the shaft actuating arm 35 and so rotate the contact shaft 45to move the contacts into and/or out of engagement.

As is more clearly seen in Figure 2 secured to either or both ends ofthe steel contact shaft 45, is a steel arm 220 and 22I. Each of thesearms carries as will be noted, two studs 223 and 224 which are rivetedin place.

Secured to one of the studs of each of the members 220 and MI is acontact opening spring the lower end of which may be attached to studsriveted to the insides of the bracket side plates. These two springs maybias the shaft towards opening position and assure quick opening.

The second of the studs for instance stud 223 on the arm 220 may beutilized to operate auxiliary switches or other devices by means, forinstance, the vertical insulated shaft 230 attached to this stud andpassing through the shelf of the bracket 30 (Fig. 2).

Thus, for instance, the vertical shaft 230 may operate auxiliary switch234 in any suitable manner for any suitable purpose. The rotation of thecontact shaft 45 towards opening position will through the arm 220 andthe stud 223 force the vertical link 230 downwardly. The vertical link230 is connected by pin 231 to the crank 232 on the shaft 233 of theswitch 234. The downward motion of the vertical link 230 will result inrotation of the crank 232 and will therefore result in rotation of theshaft 233 and in the consequent operation of the various contacts andother portions of the switch suitably connected to and actuated by shaft233.

Such switch 234 may be used where, for instance, the circuit breaker isto be connected with automatic reclosing circuits when it is open andsuch relay will obviously be reset to its original position when thesolenoid or manual closing mechanism hereinafter described rotates thecontact shaft 45 towards closing position thus raising the insulatedlink 230 and operating the switch.

As has been above pointed out, preferably three contact arms 46 aremounted on this shaft, one for each pole of the circuit breaker as seenin Figure 2. On each side of each arm, there is cemented to the shaftinsulation a Bakelite washer I43 which improves the pole to pole andpole to ground insulation.

As will be noted in Figure 2, the inter-pole washers are bevelled andflanged so that the bevelled and flanged portions I44 thereof are spacedapart so that an inter-phase barrier I45 secured to the panel may extendbetween them. The cooperation of these parts makes it impossible forany'fiexible conductors of adjacent poles to be drawn together duringheavy current flow while at the same time any possibility of arcing overis obviated.

In the construction and arrangement of the contacts, the movable maincontact is supported by an operating arm on the contact bar or shaft andis connected to the lower stud by a flexible shunt of suitable size.

Pressurev on the main contact is obtained through the use of acompression type coil spring, mounted outside the current path, and,consequently, is unaffected by heating.

The pressure on the arcing contacts is also obtained by the same type ofcompression type coil spring protected from the arc.

The main contacts are protected by the sequence of operation in openingor closing of the device, since the main contacts close after the arcingcontacts and open before them.

Although with the construction herein described, replacement of thecontacts should not be necessary, the arrangement of the movable maincontact lever and the movable arcing contact is such that access to bothstationary and movable parts with a minimum amount of labor is possible.

As hereinafter described, accessibility of the main contacts is suchthat it is necessary only to remove one screw from the arc quencherassembly and lift it off manually so as to reach the contacts. Inaddition, as is hereinbefore described, the removal of the two bearingsI40 of the main contact shaft and pigtails is sufficient to makeavailable all parts of the contact mechanism for replacement, cleaningor repair.

The individual poles of the circuit breaker are each rigidly mounted ona rigid insulating shaft so as to insure the simultaneous opening andclosing of all contacts. The use of a single trip free mechanismoperating the main contact shaft also insures that all of the poles willoperate simultaneously and precludes the possibility of openingindividual poles without opening others.

An important feature of the present invention is that the same structuremay be used for single pole or multi-pole operation, that is, as seenfor instance in the structure of Figure 2, the circuit breaker mechanismis so arranged that three poles are simultaneously operated by a singleclosing and tripping mechanism. The same type of structure may be soarranged as to take one, two or four poles or more.

Arc chute, arc horns and blow out in the actual operation of the contactassemblies herein described, when the contacts are fully closed and thelatches are then tripped, the contact shaft 45 and the contact arm 46rotate in a counterclockwise direction in the views of Figures 3 and 4.As the arm and the contact pivot pins 76 and I53 move away from thestationary contacts, the springs 69 and 85 maintain the moving contactsin engagement with the. stationary contacts until in the rotation of thecontact levers these levers l5 and 60 strike their respective stops.

During this movement, the lower end 12 of the contact lever 60 strikesthe part of the contact arm 45 which surrounds the shaft 45. At thispoint in the movement, the main contacts separate while the arcingcontacts are still engaged. It is thus seen that the circuit through themain contacts is interrupted and all the current is transferred to thecircuit of the blow out coil I22 and the arcing contacts. The core I35therefore and its associated pole pieces are highly magnetized inproportion to the current flowing.

As seen in Figures 2, 3, 4 and 5 surrounding each pole is an arc chuteI55 comprising side plates I5I of insulating material and supportingbetween them five shorter parallel spaced plates I52 also of fiber.

The entire group is held together preferably by rivets I53, I53 makingas far as possible a rigid assembly. Preferably, the rivets comprise, asseen in Figure 5, a central metal tube-like arrangement I54 and an outerinsulating cylinder I55.

As seen in Figures 5 and 4, near the panel 23, the inside plates I52 areseparated by fiber members I56 which prevent the arc gases from comingin contact with the panel and which also comprise hooks I51 which engageunder the hook or lip I55 of the stationary arcing contact member I23 inorder to assist in supporting the are quencher assembly. This iseffected by the fact that the fiber hook on the barrier herein describedis held snugly between the hook of the arcing horn and the upper currentsurface of the horn. Near the front of the arc chute is secured anarcing horn I55 which is electrically connected to an angle-clip IBI,being connected thereto by the screw I62 passing through the flange I63of the arcing horn and a flange of the angle clip. 7

The metallic clip I5I is secured by the screw I54, and lock washer I55to the bridge 37 of molded insulating material. This metallic clip I6Iis electrically connected to the flexible conductor I which in turnconnects it to the lower terminal 04. At the end of the opening movementof the arcing contact the tip 61 of the movable arcing contact 15 movesunder the stationary arcing horn I60 in the manner shown in Figure 4 sothat the arc terminal is transferred to the stationary arcing horn I60and the current flows through the conductor I00 to the lower terminalblock 44. The current is first transferred from the main contacts to thearcing contacts, and, when the arc is then transferred to the stationaryarcing contact or horn I60, the movable arcing contact is shunted out ofthe circuit.

As seen in Figure 2, the blow out core I30 extends beyond the sides ofthe blow out coil 22 a distance equal to the thickness of the insulatingside plates I5I. I

The insulating side plates are notched at I15, as seen in Figure 1, sothat they may embrace the core I30 while their edges rest against thepanel 23. By this arrangement, any possible impediment to the magneticfluxes induced by the core in the pole pieces hereinafter described isobviated.

Ferrous blow out plates or pole pieces I16. Figures 1, 2 and 5, aresecured to the outer surfaces of the side plates I5I of the arc chute bymeans of rivets or other suitable attaching means I11. These blow outplates or pole pieces, as seen particularly in Figure 1, cover a part ofthe notch I15 in the insulating plates I5I so that when the arc chutesare in position against the panel 23 and in proper relation to thecontact assembly, the surface of each end of the core I is in contactwith a corresponding iron blow out plate or pole piece I16.

Each of the side plates has its back edge I80 (Figure l) bevelled on theinner side thereof so that it may be slid in position easily past thenotches of the insulated bridge hereinafter described.

The notch I15 around the blow out core I30 (Figure 1) and the lip I39 onthe stationary arcing contact I23 which engages the hook I51 of thefiber spacer I56 of the arc chute I50 (Figure 3) assist in positioningthe back end of the arc chute in proper relation to the panel 23 and thevarious other portions of the contact assembly.

The front of the arc chute is supported by the metallic clip I6I whichis secured to the insulating bridge 31 and in current carrying contactwith the conductor I00 by the screws I64 and its lock washer I65. Thescrew I62 provides a releasable clamping means between the arcing hornI60 and the clip I6I to maintain the arc chute in operative position. v

The front end of the arc chute is therefore securely positioned in placeby means of the screws I64 and I62. It will be noted that removal of thescrew I62 will permit the withthe arcing contact I23 and as seen inFigure l, the notch I15 of the outer plate I5I may by the same motionslide out of engagement with the blow out core I30. The are chutetherefore is so arranged that a simple unscrewing of the screw I62 willpermit removal thereof.

" It should be notedthat the screw I62 is so arranged that it need notbe completely removed but it may be rotated a sufficient number of turnsto disengage it from the clip I6I and may remain in the portion I63 ofthe arcing horn I during removal of the arc chute. By this simplifiedmeans involving rotation of a single screw, the arc chute may besecurely mounted in place or quickly removed by a single motion in ahorizontal direction.

The are splitting plates I52 (five in number in the preferredembodiment) have, as seen in Figures 3 and 4, their lower edges shapedin two arcs I and I9I which are concave in a; downward direction withthe cusp I92 between them rounded. This cusp lies approximately midwaybetween the stationary arcing horn I23 and the front arcing'horn I60.The downwardly extending cusps facilitate the entrance of the are intothe slots between the plates and are so arranged that a relatively smalllongitudinal length of the arc is first forced between the plates and sothat as the arc is blown upwardly, progressively greater lengths of thearc are forced between the plates.

As is also seen in Figures 3, 4 and 5, the lower edges of the plates I52are of different heights, the middle one I52a being the highest and theouter plates I520 being the lowest, that is, extending downwardly agreater distance. The intermediate plates I52b are of a height so thatthe lower edges extend in planes substantially between the position ofthe edges of the middle and outer members.

As is also seen in Figures 3 and 4, the five plates here shown haveperforations I95 of suitable size and shape, spaced and arranged topermit the flow of arc gases from the slot I96 (Figure 5) between onepair of plates to the slot between another. In order to provide a moreturbulent condition of the arc gases and in order to insure contact ofthe arc gases with the various plates, the holes or perforations I95 ofeach of the plates are in staggered relation with respect to those inadjacent plates.

Upon opening of the main contacts and formation of the are between thearcing contacts 14 and I23, the arc is immediately transferred from thearcing tip 14 to the arcing horn I60.

The current flowing through the coil I22 energizes the magnet comprisingcore I30 and ferrous plates I16 producing a flux across the arc space.This flux forces the arc upwards towards and into the arc chute I50."When the arc reaches the lower edges of the arc splitters or plates I52it is squeezed or .fiattened to be forced between the two outer platesI520 and I520. Further movement forces the arc between the intermediateplates I52b-I52b further reducing its horizontal width.

As the arc is pushed further it may enter one of the slots I96 or it maybe divided longitudinally in two or more slots. ln'either case, the arcgases have an opportunity to expand through the holes I95 in the platesI52.

This provision for permitting the arc gases to expand from slot to slotreduces the back pressure and hence permits the blow out magnet to forcethe arc upward at full speed.

The tendency of the ionized gases discharged from one slot to enteranother through the perforat1ons I95 permits parallel arcs to exist oversections of the are. This causes greater instability and increasedtendency to'speed the extinguishing of the arc.

By this means also a large cooling area is provided which furthercontributes to shorten the arcing time. Preferably the arc gases aresufficiently cooled and deionized by the arc quencher so that when, inthe case of alternating current, the current passes through zero in thecycle immediately following the formation of the arc, the gases will besufliciently deionized to provide an extremely difficult path for an arcand thus prevent the re-striking thereof. The are therefore may bequenched with of a second of the formation thereof.

I rater-phase barriers Suificient inter-phase barriers are provided bythe side plates l5! of the arc chute. However, additional inter-phasebarrier plates M5 (Figures 1-4 inclusive) may be used to make itimpossible for any flashing over of the are from one pole to the other.These inter-phase barriers are placed between the arc chutes and carriedup so that they are aligned with the top of the panel 23 and may besecured to the panel by suitable blocks 200 of insulating material; theblocks 200 of insulating material are secured to one side of theinter-phase barriers at the top. These blocks are drilled to receive thescrew 28! which threads into a plug in the panel to secure the barrierin position.

As will also be seen in Figure l, the interphase barrier I45 extendsbeyond the arc chute both at the top and the front. The front lowercorner rests on the insulation bridge 31 while as has been beforepointed out, the back end bears against the panel and extends downbetween the shaft. insulation disks I43-l43.

Lower inter-phase barriers Iilfia (Figure 1) are aligned with the upperinter-phase barriers and secured to the panel 23 by screws Hlla and [02athus preventing any tendency of the flexible leads to approach eachother or any current at that point from arcing over.

The lower back corner of the upper interphase barrier is supported by astrip of insulating material secured to the panel just above the top ofthe housing brackets. The lower interphase barriers align with the upperones and are secured to the panel by screws threaded into their edge.These lower barriers are notched to surround the shaft. They prevent theflexible conductors from being drawn together during fault current.

Various other elements may, of course, be utilized in connection withthe circuit breaker mechanism. Thus, for instance, as seen in Figure 2,a suitable time delay element 950 may be providedin connection with theover current coil Hi] to permit the breaker to carry normal load aboveits trip setting for short periods of time. The specific details of thetime delay elements are not herein discussed since they constitute nopart of the present invention.

The operation and function of each of the parts of the arc chute of thepresent invention and the cooperation thereof with the elements of thecircuit breaker have been set forth in connection with the specificdescription of each of said parts.

In the foregoing, I have described only those parts of the circuitbreaker necessary to fully understand the operation of the arc quencherand the arc-splitting plates. The various constructions herein describedmay be modified in many ways which will now be obvious to those skilledin the art.

Accordingly, I prefer to be bound, not by the specific disclosuresherein, but only by the appended claims.

This application embodies portions of the structures of the applicationof Frank J. P0- korny, for Circuit breaker operating mechanism, SerialNo. 339,682, the application of William Maxwell Scott, Jr., for Circuitbreaker, Serial No. 339,687, the application of William Maxwell Scott,Jr., for Stationary contact structure, Serial No. 339,688, and theapplication of William Maxwell Scott, Jr., for Circuit breakermovablecontacts, Serial No. 339,689, all filed June 10, 1940. In thisapplication I have claimed those inventions and portions of thestructure devised by me.

I claim:

1. An arc extinguisher comprising a plurality f spaced parallel barrierplates insulatedly mounted between a pair of side plates, said platesextending in planes parallel to the axis of the arc, ferrous platesmounted on the outer sides of said side plates forming a path formagnetic blow-out fluxes, said ferrous plates being registerable withthe ends of the magnetic core of a blow-out coil, said barrier plates,side plates and ferrous plates forming a single integral unit mountableand removable as a unit upon a circuit breaker, said unit carrying ahook at the rear end engageable with coacting means on the circuitbreaker panel and a single releasable screw threaded means at the frontend engageable with cooperating means on the circuit breaker forsecuring the front of the are extinguisher in position.

2. An arc extinguisher for extinguishing an are drawn between opposedcontacts, said are extinguisher comprising a plurality of spacedparallel barrier plates insulatedly mounted between a pair of sideplates, said plates extending in planes parallel to the axis of the arc,ferrous plates mounted on the outer sides of said side plates forming apath for magnetic blow-out fluxes, said ferrous plates being registerable with the ends of the magnetic core of a blow-out coil, saidbarrier plates, side plates and ferrous plates forming a single integralunit mountable and removable as a unit upon a circuit breaker, said unitcarrying a hook at the rear end engageable with coacting means on thecircuit breaker panel and means at the front end engageable withcooperating means on the circuit breaker, said coacting means on thecircuit breaker panel comprising an extension of an arcing horn, saidunit carrying an arcing horn at the front end, and means for connectingsaid latter arcing horn in the arcing circuit. said unit being removablefrom said circuit breaker panel by a movement substantially parallel tothe movement of the contacts.

3. An arc extinguisher comprising a plurality of spaced parallel barrierplates insulatedly mounted between a pair of side plates, said platesextending in planes parallel to the axis of the arc, ferrous platesmounted on the outer sides of said side plates forming a path formagnetic blow-out fluxes, said ferrous plates being registerable withthe ends of a magnetic core of a blow-out coil, said barrier plates,side plates and ferrous plates forming a single integral unit mountableand removable as a unit upon a circuit breaker, an insulating supportingbridge at the front of the circuit breaker, the forward bottom edges ofthe side plates engageable with said bridge for supporting the forwardend thereof, and means at the rear end of the unit engageable byhorizontal movement of the unit with coacting means on the circuitbreaker for supporting the rear end thereof.

4. In a circuit breaker mounted on a panel, an insulating supportingbridge supported at a distance from the panel; a blow-out coil includingan arcing horn secured to said panel and an arcing contact structuresecured to said panel and partially encasing said blow-out coil, ahooked. extension on said arcing contact, said blow out coil having acore extending beyond the ends of said coil, an arc extinguisher havingside plates of insulating material provided with notches engageable withsaid extensions of said core, said side plates carrying ferrous platesregisterable with the ends of said core, and a hooked member in said areextinguisher engageable with said hooked extension on said arcingcontact by horizontal movement of said are extinguisher, an insulatingbridge supported by and spaced from said panel the other end of said arcextinguisher being supportable on said insulating bridge, an arcing hornsupported in said are extinguisher at said other end.

5. In a circuit breaker mounted on a panel, an insulating supportingbridge supported at a distance from the panel; a blow-out coil securedto said panel and an arcing contact structure secured to said panel andpartially encasing said blow-out coil, a hooked extension on said arcingcontact and a removable arc extinguisher, said blow out coil having acore extending beyond the ends of said coil, said are extinguisherengageable with said extensions of said core, said side plates carryingferrous plates registerable with the ends of said core, and a hookedmember in said are extinguisher engageable with said hooked extension onsaid arcing contact, the other end of said are extinguisher beingsupportable on said insulating bridge, an arcing horn supported in saidare extinguisher at said other end; said arcing contact structure alsocomprising an arcing horn, a metallic member on said insulating bridgeand means for connecting said first arcing horn to said metallic member,said member being connected to a terminal of the circuit, said secondmentioned arcing horn being connected through the blow-out coil toanother terminal of the current supply.

6. In a circuit breaker mounted on a panel, an insulating supportingbridge supported at a distance from the panel; a blow-out coil securedto said panel and an arcing contact structure secured to said panel andpartially encasing said blow-out coil, a hooked extension on said arcingcontact and a removable arc extinguisher, said blow out coil having acore extending beyond the ends of said coil, said are extinguisherengageable with said extensions of said core, said side plates carryingferrous plates registerable with the ends of said core, and a hookedmember in said are extinguisher engageable with said hooked extension onsaid arcing contact, the other end of said arc extinguisher beingsupportable on said insulating bridge, an arcing horn supported in saidarc extinguisher at said other end; said arcing contact structure alsocomprising an arcing horn, a metallic member on said insulating bridge,and means for connecting said first arcing horn to said metallic member,said connecting means comprising a releasable member engageable withsaid metallic member and an end of said first arcing horn, said areextinguisher being removable from the circuit breaker assembly uponrelease of said releasable member.

'7. In a circuit breaker mounted on a panel, an insulating supportingbridge supported at a distance from the panel; a blow-out coil securedto said panel and an arcing contact structure secured to said panel andpartially encasing said blow-out coil, a hooked extension on said arcingcontact and a removable arc extinguisher, said blow-out coil having acore extending beyond the ends of said coil, said arc extinguisherengageable with said extensions of said core, said side plates carryingferrous plates registerable with the ends of the core, and a hookedmember in said are extinguisher engageable with said hooked extension onsaid arcing contact, the

, other end of said arc extinguisher being supportable on saidinsulating bridge, an arcing horn supported in said are extinguisher atsaid other end; said arcing contact structure also comprising an arcinghorn, a metallic member on said insulating bridge, and means forconnecting said first arcing horn to said metallic member, saidconnecting means comprising a screw engageable with openings in saidmetallic member, and an end of said first arcing horn, said areextinguisher being removable from the circuit breaker assembly uponrotation of said screw.

8. In a circuit breaker mounted on a panel, a removable arcextinguisher, means for positioning said extinguisher comprising meanson said panel engageable with cooperating elements on one end of saidextinguisher and an insulating member supported in spaced relation tosaid panel engageable with the other end of said extinguisher, saidother end of said are extinguisher carrying an arcing horn, and a.single means for securing said end of said arcing horn to saidinsulating member and connecting said arcing horn in an arcing circuit.

9. L1 a circuit breaker mounted on a panel, a blow-out coil secured tosaid panel, and an arcing contact structure secured to said panel andpartially encasing said blow-out coil, a hooked extension on said arcingcontact and a removable arc extinguisher, said blow-out coil having a.core extending beyond the ends of said coil, said are extinguisherengageable with said extensions of said core, said side plates carryingferrous plates registerable with the ends of said core, said arcextinguisher comprising a series of barrier plates with hooked shapedmembers therebetween, said hook members being engageable with saidhooked extension on said arcing contact.

10. In a circuit interrupter an arc chute comprising a pair of spacedside plates of insulating material, magnetic plates positioned on theoutside of said insulating plates, spacing means between said insulatingplates, means securing said magnetic plates, insulating plates andspacing means together, insulating supporting means, a pair of contactstructures on said supporting means for connection in an electriccircuit, one of said structures comprising a conducting coil and amagnetic core therefore extending axially beyond the dimensions of saidcoil, notches in said insulating plates adapted to embrace the ends ofsaid core when said are chute is in operative position, said magnetitcplates covering said notches to engage the ends of said core, an arcinghorn associated with said coil and secured to said supporting means, ahorizontal groove in said arcing horn, one of said spacing means forsaid plates cooperating with said groove for positioning one end of saidare chute, a bracket mounted on said insulating supporting means andadditional spacing means cooperating with said bracket for positioningthe other end of said are chute.

11. In a circuit interrupter an arc chute comprising a pair of spacedside plates of insulating material, magnetic plates positioned on theoutside of said insulating plates, spacing means between said insulatingplates, means securing said magnetic plates, insulating plates andspacing means together, insulating supporting means, a pair of contactstructures on said supporting means for connection in an electriccircuit, one of said structures comprising a conducting coil and amagnetic core therefor extending axially beyond the dimensions of saidcoil, notches in said insulating plates adapted to embrace the ends ofsaid core when said arc chute is in operative position, said magneticplates covering said notches to engage the ends of said core, an arcinghorn associated with said coil and secured to said supporting means, ahorizontal groove in said arcing horn, one of said spacing means forsaid plates cooperating with said groove for positioning one end of saidarc chute, a bracket mounted on said insulating supporting means andaddi tional spacing means cooperating with said bracket for positioningthe other end of said are chute, said additional spacing meanscomprising clamping means cooperating with said bracket to precludemovement of said are chute relative to said insulating supporting meansuntil after release of said clamping means.

12. In a circuit interrupter an arc chute comprising a pair of spacedside plates of insulating material, a plurality of spacing means betweensaid plates and means for securing said insulating plates and spacingmeans together, insulating supporting means, a contact structure mountedon said supporting means, said contact structure comprising a groovehaving its opposed surfaces in horizontal planes, one of said spacingmeans cooperating with said groove for positioning one end of said arcchute, a bracket mounted on said insulating supporting means andadditional spacing means cooperating with said bracket for positioningthe other end of said chute.

13. In a circuit interrupter an arc chute comprising a pair of spacedside plates of insulating material, a plurality of spacing means betweensaid plates and means for securing said insulating plates and spacingmeans together insulating supporting means, a contact structure mountedon said supporting means, said contact structure comprising a groovehaving its opposed surfaces in horizontal planes, one of said spacingmeans cooperating with said groove for positioning one end of said arcchute, a bracket mounted on said insulating supporting means andadditional spacing means cooperating with said bracket for positioningthe other end of said chute, said additional spacing means comprising ametallic arcing horn.

14. In a circuit interrupter an arc chute comprising a pair of spacedside plates of insulating material, a plurality of spacing means betweensaid plates and means for securing said insulating plates and spacingmeans together, insulating supporting means, a contact structure mountedon said supporting means, said contact structure comprising a groovehaving its opposed surfaces in horizontal planes, one of said spacingmeans cooperating with said groove for positioning one end of said arcchute, a bracket mounted on said insulating supporting means andadditional spacing means cooperating-with said bracket for positioningthe other end of said chute, said additional spacing means comprising ametallic arcing horn; a, second contact structure mounted on saidinsulating supporting means and conducting means connecting saidadditional spacing means and said second contact structure.

' 15. In a circuit interrupter an arc chute comprising a, pair of spacedside plates of insulating material, a plurality of spacing means betweensaid plates and means for securing said insulating plates and spacingmeans together, insulating supporting means, a contact structure mountedon said supporting means, said contact structure comprising a groovehaving its opposed surfaces in horizontal planes, one of said spacingmeans cooperating with said groove for positioning one end of said arcchute, a bracket mounted on said insulating supporting means andadditional spacing means cooperating with said bracket for positioningthe other end of said chute, said additional spacing means comprising ametallic arcing horn; a second contact structure mounted on saidinsulating supporting means and conducting means connecting saidadditional spacing means and said second contact structure, one end ofsaid conducting means being insulatedly secured to said bracket, forcooperation with said additional spacing means and the other end of saidconducting means being secured to said second contact structure.

16. In a circuit interrupter an arc chute comprising a pair of spacedside plates of insulating material, a plurality of spacing means betweensaid plates and means for securing said insulating plates and spacingmeans together, insulating supporting means, a contact structure mountedon said supporting means, said contact structure comprising a groovehaving its opposed surfaces in horizontal planes, one of said spacingmeans cooperating with said groove for positioning one end of said arcchute, a bracket mounted on said insulating supporting means andadditional spacing means cooperating with said bracket for positioningthe other end of said chute, and detachable clamping means between saidadditional spacing means and said conducting means for precludingmovement of said are chute relative to said insulating supporting meansuntil after release of said clamping means.

17. In a circuit interrupter an arc chute comprising a pair of spacedside plates of insulating material, magnetic plates positioned on theoutside of said insulating plates, spacing means between said insulatingplates, means securing said magnetic plates, insulating plates andspacing means together, insulating supporting means, a pair of contactstructures on said supporting means for connection in an electriccircuit, one of said structures comprising a conducting coil and amagnetic core therefor extending axially beyond the dimensions of saidcoil, notches in said insulating plates adapted to embrace the ends ofsaid core when said arc chute is in operative position, said magneticplates covering said notches to engage the ends of said core, an arcinghorn associated with said coil and secured to said supporting means, ahorizontal groove in said arcing horn, one of said spacing means forsaid plates cooperating with said groove for positioning one end of saidarc chute, a bracket mounted on said insulating supporting means andadditional spacing means cooperating with said movable contact structureand operating mech- 10 anism therefor, .a member .of insulating materialsecured to said bracket and .a plurality of .arc extinguishers eachhaving one end supported by the respective stationary contact structure,and the otherlend releasablysecured to said member; andan arcing horncarried in said other end .of each .arc extinguisher; the means forsecurin saidother end to said member ,also connecting said arcing hornin the arcing circuit.

FRANK J. POKORNY.

